The present invention relates to novel compounds that are useful for inhibition, alteration, or prevention of cell adhesion and cell adhesion-mediated pathologies. This invention also relates to methods of identifying additional novel compounds having the desired activity, as well as to pharmaceutical formulations comprising these compounds, and methods of using them for inhibition and prevention of cell adhesion and cell adhesion-mediated pathologies. The compounds and pharmaceutical compositions of this invention can be used as therapeutic or prophylactic agents. They are particularly well-suited for the treatment of many inflammatory and autoimmune diseases.
Cell adhesion is a process by which cells associate with each other, migrate towards a specific target or localize within the extra-cellular matrix. As such, cell adhesion constitutes one of the fundamental mechanisms underlying numerous biological phenomena. For example, cell adhesion is responsible for the adhesion of hematopoietic cells to endothelial cells and the subsequent migration of those hematopoietic cells out of blood vessels and to the site of inflammatory injury. As such, cell adhesion plays a role in numerous pathologies such as, for example, inflammation and immune reactions in mammals.
Investigations into the molecular basis for cell adhesion have revealed that various cell-surface macromoleculesxe2x80x94collectively known as cell adhesion molecules or receptorsxe2x80x94mediate cell-cell and cell-matrix interactions. For example, proteins of the superfamily called xe2x80x9cintegrinsxe2x80x9d are key mediators in adhesive interactions between hematopoietic cells and their micro environment (M. E. Hemler, xe2x80x9cVLA Proteins in the Integrin Family: Structures, Functions, and Their Role on Leukocytes.xe2x80x9d, Ann. Rev. Immunol., 8, p. 365 (1990)). Integrins are non-covalent heterodimeric complexes consisting of two subunits called xcex1 and xcex2. There are at least 16 different xe2x80x9csubunits (xcex11-xcex19, xcex1-L, xcex1-M, xcex1-D, xcex1-X, xcex1IIB, xcex1-V and xcex1-E) and at least 9 different xcex2 (xcex11-xcex19) subunits which have been identified to date. Based on the type of its a and xcex1 and xcex2 subunit components, each integrin molecule can be categorized into a subfamily.
xcex14xcex21 integrin, also known as very late antigen of activation-4 (xe2x80x9cVLA-4xe2x80x9d) or CD49d/CD29, is a leukocyte cell surface receptor that participates in a wide variety of both cell-cell and cell-matrix adhesive interactions (M. E. Hemler, Ann. Rev. Immunol., 8, p. 365 (1990)). It serves as a receptor for the cytokine-inducible endothelial cell surface protein, vascular cell adhesion molecule-1 (xe2x80x9cVCAM-1xe2x80x9d), as well as to the extracellular matrix protein fibronectin (xe2x80x9cFNxe2x80x9d) (Ruegg et al., J. Cell Biol., 177, p. 179 (1991); Wayner et al., J. Cell Biol., 105, p. 1873 (1987); Kramer et al., J. Biol. Chem., 264, p. 4684 (1989); Gehlsen et al. Science, 24, p. 1228 (1988)). Anti-VLA4 monoclonal antibodies (xe2x80x9cmAb""sxe2x80x9d) have been shown to inhibit VLA4-dependent adhesive interactions both in vitro and in vivo (Ferguson et al. Proc. Natl. Acad Sci., 88, p. 8072 (1991); Ferguson et al., J. Immunol., 150, p. 1172 (1993)). Results of in vivo experiments suggest that the inhibition of VLA-4-dependent cell adhesion may prevent, inhibit or alter several inflammatory and autoimmune pathologies. (R. L. Lobb et al., xe2x80x9cThe Pathophysiologic Role of xcex14 Integrins In Vivoxe2x80x9d, J. Clin. Invest., 94, pp. 1722-28 (1994)).
Another integrin, xcex1IIbxcex2IIIa integrin (xe2x80x9cIIb/IIIaxe2x80x9d), is the most abundant integrin found on the membrane surface of normal platelets. Jennings, et al., J. Biol. Chem., 257, p. 10458 (1982). Platelets depend on the adhesive interactions of glycoproteins, such as xe2x80x9cIIb8IIIa integrin, for proper function. J. Hawiger, Atherosclerosis Reviews, 21, pp. 165-86 (1990). Thus, inhibition of this interaction is one method of regulating platelet thrombus formation or aggregation. A variety of compounds are known to inhibit xcex1IIbxcex2IIIa integrins from binding to their natural ligands and thereby can regulate human disorders associated with a hyperthrombotic state. Compounds known to inhibit IIb/IIIa are described in the following patents and patent applications: GB 2 271 567 A; GB 2 292 558 A; EP 0 645 376 A1; EP 0 668 278 A1; EP 0 608 759 A2; EP 0 635 492 A1; WO 94/22820; U.S. Pat. No. 5,340,798 and WO 94/09029; U.S. Pat. No. 5,256,812, EP 0 381 033 and U.S. Pat. No. 5,084,466; WO 94/18981; WO 94/01396 and U.S. Pat. No. 5,272,162; WO 94/21602; WO 94/22444; WO 94/29273; WO 95/18111; WO 95/18619; WO 95/25091; WO 94/18162, U.S. Pat. No. 5,220,050 and WO 93/16038; U.S. Pat. No. 4,879,313 and EP 0 352 249 B1; WO 93/16697, U.S. Pat. No. 5,227,490, EP 0 478 363 A2, U.S. Pat. No. 5,229,616 and WO 94/12181; U.S. Pat. No. 5,258,398 and WO 93/11759; WO 93/08181 and EP 0 537 980 A1; WO 93/09133; EP 0 530 505 B1; EP 0 566 919 A1; EP 0 540 334 B1; EP 0 560 730 A2; WO 93/10091, EP 0 542 363 A2 and WO 93/14077; EP 0 505 868 B1; EP 0 614 664 A1; U.S. Pat. Nos. 5,358,956; 5,334,596 and WO 94/26745; WO 94/12478; WO 94/14776; WO 93/00095; WO 93/18058, WO 93/07867, U.S. Pat. Nos. 5,239,113, 5,344,957 and EP 0 542 708 A1; WO 94/22825; U.S. Pat. No. 5,250,679 and WO 93/08174; U.S. Pat. No. 5,084,466; EP 0 668 278 A1; U.S. Pat. No. 5,264,420; WO 94/08962; EP 0 529 858; U.S. Pat. No. 5,389,631; WO 94/08577; EP 0 632 016; EP 0 503 548; EP 0 512 831 and WO 92/19595; WO 93/22303; EP 0 525 629; EP 0 604 800; EP 0 587 134; EP 0 623 615; EP 0 655 439; U.S. Pat. No. 5,446,056 and WO 95/14682; U.S. Pat. No. 5,399,585; WO 93/12074; EP 0 512 829; EP 0 372 486 and U.S. Pat. No. 5,039,805; EP 0 632 020 and U.S. Pat. No. 5,494,922; U.S. Pat. No. 5,403,836; WO 94/22834; WO 94/21599; EP 0 478 328; WO 94/17034 WO 96/20192, WO 96/19223, WO 96/19221, WO 96/19222, EP 727425, EP 478362, EP 478363, U.S. Pat. Nos. 5,272,158, 5,227,490, 5,294,616, 5,334,596, EP 645376, EP 711770, U.S. Pat. No. 5,314,902, WO 94/00424, U.S. Pat. No. 5,523,302, EP 718287, DE 4446301, WO 96/22288, WO 96/29309, EP 719775, EP 635492, WO 96/16947, U.S. Pat. No. 5,602,155, WO 96/38426, EP 712844, U.S. Pat. No. 5,292,756, WO 96/37482, WO 96/38416, WO 96/41803, WO 97/11940
Each of these references is specifically incorporated herein in its entirety.
In order to identify the minimum active amino acid sequence necessary to bind VLA-4, Komoriya et al. synthesized a variety of overlapping peptides based on the amino acid sequence of the CS-1 region (the VLA-4 binding domain) of a particular species of fibronectin. (xe2x80x9cThe Minimal Essential Sequence for a Major Cell Type-Specific Adhesion Site (CS1) Within the Alternatively Spliced Type III Connecting Segment Domain of Fibronectin Is Leucine-Aspartic Acid-Valinexe2x80x9d, J. Biol. Chem., 266 (23), pp. 15075-79 (1991)). They identified an 8-amino acid peptide, Glu-Ile-Leu-Asp-Val-Pro-Ser-Thr, SEQ ID NO. 1 as well as two smaller overlapping pentapeptides, Glu-Ile-Leu-Asp-Val SEQ ID NO. 2 and Leu-Asp-Val-Pro-Ser SEQ ID NO. 3, that possessed inhibitory activity against FN-dependent cell adhesion. These results suggested that the tripeptide Leu-Asp-Val was the minimum sequence for cell-adhesion activity. It was later shown that Leu-Asp-Val binds only to lymphocytes that express an activated form of VLA-4, thus casting doubt on the utility of such a peptide in vivo (E. A. Wayner et al., xe2x80x9cActivation-Dependent Recognition by Hematopoietic Cells of the LDV Sequence in the V Region of Fibronectinxe2x80x9d, J. Cell. Biol., 116(2), pp. 489-497 (1992)). However, certain larger peptides containing the LDV sequence were subsequently shown to be active in vivo (T. A. Ferguson et al., xe2x80x9cTwo Integrin Binding Peptides Abrogate T-cell-Mediated Immune Responses In Vivoxe2x80x9d, Proc. Natl. Acad. Sci. USA, 88, pp. 8072-76 (1991); and S. M. Wahl et al., xe2x80x9cSynthetic Fibronectin Peptides Suppress Arthritis in Rats by Interrupting Leukocyte Adhesion and Recruitmentxe2x80x9d, J. Clin. Invest., 94, pp. 655-62 (1994)).
A cyclic pentapeptide, Arg-Cys-Asp-TPro-Cys SEQ ID NO. 4 (wherein TPro denotes 4-thioproline), which can inhibit both VLA-4 and VLA-5 adhesion to FN has also been described. (See, e.g., D. M. Nowlin et al. xe2x80x9cA Novel Cyclic Pentapeptide Inhibits xcex14xcex21 and xcex15xcex21 Integrin-mediated Cell Adhesionxe2x80x9d, J. Biol. Chem., 268(27), pp. 20352-59 (1993); and PCT publication PCT/US91/04862). This pentapeptide was based on the tripeptide sequence Arg-Gly-Asp from FN which had been known as a common motif in the recognition site for several extracellular-matrix proteins.
Examples of other VLA-4 inhibitors have been reported, for example, in copending U.S. patent application Ser. No. 08/376,372, specifically incorporated by reference herein. U.S. Ser. No. 376,372 describes linear peptidyl compounds containing b-amino acids which have cell adhesion inhibitory activity. International patent applications WO 94/15958 and WO 92/00995, specifically incorporated by reference, describe cyclic peptide and peptidomimetic compounds with cell adhesion inhibitory activity. International patent applications WO 93/08823 and WO 92/08464 (specifically incorporated by reference herein) describe guanidinyl-, urea- and thiourea-containing cell adhesion inhibitory compounds. U.S. Pat. No. 5,260,277 describes guanidinyl cell adhesion modulation compounds, and is also specifically incorporated herein.
Despite these advances, there remains a need for small, potent inhibitors of cell adhesion, particularly for potent inhibitors of VLA-4 or IIb/IIIa cell adhesion. Ideally, such inhibitors would be small so that they may be administered orally. Such compounds would provide useful agents for treatment, alteration, prevention or suppression of various pathologies mediated by cell adhesion and VLA-4 or IIb/IIIa binding.
The present invention solves this problem by providing novel compounds that inhibit cell adhesion, and, specifically, the binding of ligands to VLA-4. These compounds are useful for inhibition, prevention and suppression of VLA-4-mediated cell adhesion, and pathologies associated with that adhesion, such as inflammation and immune reactions. The compounds of this invention may be used alone or in combination with other therapeutic or prophylactic agents to inhibit, alter, prevent or suppress cell adhesion.
The present invention thus provides novel compounds, formulations and methods which may be used in the study, diagnosis, treatment or prevention of diseases and conditions which relate to cell adhesion, including, but not limited to arthritis, asthma, allergies, adult respiratory distress syndrome, cardiovascular disease, thrombosis or harmful platelet aggregation, allograft rejection, neoplastic disease, psoriasis, multiple sclerosis, CNS inflammation, Crohn""s disease, ulcerative colitis, glomerular nephritis and related inflammatory renal disease, diabetes, ocular inflammation (such as uveitis), atherosclerosis, inflammatory and autoimmune diseases. This invention also provides pharmaceutical formulations containing these VLA-4-mediated cell adhesion inhibitors and methods of using the compounds and compositions of the invention for inhibition of cell adhesion.
According to one embodiment of this invention, these novel compounds, compositions and methods are advantageously used to treat inflammatory and immune diseases. The present invention also provides methods for preparing the compounds of this invention and intermediates useful in those methods.
Accordingly, the present invention relates to cell adhesion inhibitors comprising a compound having Formula (I)
A-Bxe2x80x83xe2x80x83(I)
where A comprises a specificity determinant which does not impart significant IIb/IIIa activity, and B comprises an integrin scaffold. More specifically, the present invention relates to a compound of Formula (I) having VLA-4 inhibitory activity and an integrin scaffold derived from a compound having IIb/IIIa activity.
In other embodiments, the claimed invention relates to preferred VLA-4 inhibitors wherein B is chosen from the integrin scaffolds of the compounds set forth in Table 2, or more preferably, from the scaffolds identified in the compounds in Table 1. Further, most preferred compounds are those in table 3, and preferred scaffolds, as well as preferred specificity determinants, are those derived from the compounds exemplified in Tables 1, 2 and 3.
Additionally, the present invention relates to methods of making cell adhesion inhibitors, generally, by removing the IIb/IIIa specificity determinant from a IIb/IIIa inhibitor, and replacing said specificity determinant with a VLA-4 specificity determinant, thereby creating a novel, heretofore undescribed, VLA-4 inhibitor.
More specifically, the methods of making the cell adhesion inhibitors of the invention comprise the steps of providing a first compound having IIb/IIIa inhibitory activity. The first compound comprises a IIB/IIIa specificity determinant, comprising a basic nitrogen functionality, which, for example, may be a phenylamidine moiety, and an integrin scaffold. One removes the phenylamidine moiety, or, if none is present, as for example, when the nitrogen functionality is a piperidine or a benzylamine, creating a xe2x80x9cphantomxe2x80x9d phenylamidine moiety by creating phantom bonds in the para orientation, and removing unneeded bonds, as discussed in more detail below, and removing the xe2x80x9cphantomxe2x80x9d moiety. The phenylamidine moiety is then replaced with a VLA-4 specificity determinant, thereby creating a second compound, having VLA-4 specificity determinant and an integrin scaffold, and having VLA-4 activity. In certain embodiments, it may be preferable to insert an additional group at the point of, or adjacent to, the connection between the integrin scaffold and the specificity determinant, to confer desirable characteristics on the compound. Such desirable characteristics are easily determined by those skilled in the art, and may, for example, encompass such characteristics as flexibility, or structural modifications designed to alter the activities of the compound. Any suitable additional groups may be used, and are known by those skilled in the art. Preferred groups may include, but are not limited to carbonyl, carboxamide, ether, nitrogen, oxygen, sulfide, sulfur amide, and methylene.
In yet other embodiments, the method described above can be used to make a pharmaceutical composition for the treatment of a condition associated with cell adhesion. The methods described above for making VLA-4 inhibitors are followed, and then suitable pharmaceutically acceptable carriers, excipients, additives, stabilizers etc. may be added. The claimed invention also encompasses xe2x80x9ccocktailxe2x80x9d compositions, i.e. those containing the compounds of the invention in addition to other active reagents. Such compositions are discussed in more detail below.
Certain embodiments encompass methods of treating cell adhesion associated conditions in mammals by administering a therapeutically effective amount of a composition. The claimed methods of treatment are most appropriate for humans, although other mammals are also suitable subjects. Advantageously, because of the relatively small size of the compounds of the invention, the compositions are particularly suitable for oral administration in the form of a solid, liquid or suspension.